Exfo White Paper Volte Call Troubleshooting in Live Lte Network 45271
Nsn Volte White Paper
description
Transcript of Nsn Volte White Paper
Evolve to richer voice with Voice over LTE (VoLTE)
Winning the revenue advantage with LTE smartphones
NSN White paper November 2013
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CONTENTS
Voice will become data 3
Executive summary 3
1. Why implement VoLTE 4
2. VoLTEofferskeyadvantagesinfourmainareas 6
3. How to evolve to VoLTE: Approaches to consider 10
4. OptionsforprovidingvoiceservicestoLTEsmartphonesubscribers
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5. VoLTEsolution:PartofNSNLiquidNet 14
6. Conclusion 15
Glossaryofabbreviations 15
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Voice will become dataTheadoptionofLTEisfollowingtheexampleof3Ginearlythe2000s,butatamuchfasterrate.ForoperatorsevolvingtoLTE,providingvoiceononenetworkanddataonanotherdoesnotmakefinancialsense.Instead,voiceissettobecomeanintegralpartofLTEasitistodaywith2Gand3G.Asthisevolutioncontinues,LTEandVoiceoverLTE(VoLTE)arebecomingthemainstreamtechnologyandby2016,VoLTEwillaccountaround10%ofallLTEsubscriptions.
TheimplementationofVoiceofOverLTE(VoLTE)willhavefar-reachingimplicationsandwillbringmanyadvantagesforoperators,includinghigherefficiencyandlowercosts.Asvoicebecomesdata,VoLTEwillenablearichmultimediavoiceexperience,helpingtoimprovethecompetitivepositionofoperatorsagainstOTTplayers.
TheevolutiontoVoLTEwillproceeddownseveralpaths,withboththetechnologychoicesandtimingdependentonexistingtechnologies,thespectrumavailable,currentandfuturevoicestrategies,andlocalmarketconditions.AsoperatorsdecideontheappropriateLTEstrategy,whethertooptforhotspotsornationwidecoverage,forexample,theyarealsochoosingtheirapproachtoVoLTE.Insomecases,theywillstarttheirevolutiontoVoLTEwithCircuitSwitchedFallback(CSFB)andoncehavenationwideLTEcoverage,theywillimplementfull-fledgedVoLTEservice.Makingtheoptimumchoicewillbecrucialtocompetesuccessfullyinanenvironmentwherechangeisthe only constant and subscriber expectations will only increase.
• WhyimplementVoLTE? Explosive demand combined with increasing pricepressureandcompetitionfromOTTplayersaredrivingtheevolutiontoLTE,which opens up new business opportunities foroperatorsandhelpsthemimprovethecustomer experience.
• Whatarethetimelinesfortheintroduction ofVoLTE?
ThemassmarketintroductionofLTEsmartphoneshasbegun,andby2016VoLTEisprojectedtoaccountfor10%ofallLTEsubscriptions.
• WhatarethekeyadvantagesofVoLTE? VoLTEsupportshigherspectralefficiency,OPEXsavingsfromconsolidationandoptimization,bettervoicecallquality,and
newopportunitiesformoresophisticatedvoice-basedservices.
• WhatarethemainfactorsbehindthedecisiontoimplementVoLTE?
WhenoperatorsaremakingthedecisiontoimplementVoLTE,thereareseveralkeyfactorstobearinmind,includingtheirexistingmobiletechnology,theLTEspectrumandcoverageavailable,localmarketandcompetitiveconditions and their business objectives.
• WhatarethemainapproachestoimplementingVoLTE?
OperatorscanimplementfullIMSVoLTEandmultimedia,startwithCSFBforvoiceandIMSformultimedia,orrelyonCSFBoverthelongertermandtargetLTEfordata.
• VoLTEfromNokiaSolutionsandNetworks(NSN)
Executive summary
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1. Why implement VoLTEExplosivedemandfordata,greaterdemandforquality,andintensepricecompetitionarethreegoodreasonsforadoptingVoLTE.Capacityneedsareprojectedtoincrease1000-foldby2020asaveragedailyusagerisesto1GB.Atthesametime,marketdevelopmentssuchasOTTvoicearesqueezingprice-per-minuteandputtingunprecedentedpressureoncosts.Fortheirpart,subscribersincreasinglywantfaster,morereliableandricherservices,andtheyarereadyandwillingtoswapproviderstogetwhattheywant.Some40%ofhighvaluecustomersarelikelytochangeoperatorsinthenext12months.
Theseescalatingdemandsaredrivingtheintroductionofhigh-capacity,all-IPnetworks,withLTEprovidingtheradioaccessformobileconnectivity.AsLTEsmartphonescomeonthemarketandmore high-bandwidthapplicationssuchasHDvideoareintroduced,thesetrends will only accelerate.
Asthefirstradiotechnologythatisfullypacket-based,LTEprovidesfasteraccessratesandlowerlatency,aswellasenablingoperatorstoenjoyalowercost-per-transmitted-bitbyusingnetworkresourcesmoreefficiently.LTEisthekeytoprovidingcost-effectivecapacitytocatertogrowingdemandforhigh-bandwidthservicessuchasmobilevideo.
BySeptember2012,morethan290operatorshadcommittedtoLTEin93countriesandmorethan90commercialnetworkswereupandrunning.Infact,LTEis“thefastestdevelopingmobilesystemtechnologyever,”saystheGSA.
1.1 LTE provides the foundation for richer voice and data services
LTE-basedall-IPnetworksopenupopportunitiestointroducenewbusinessmodels,offerricherservicesandenhancebusinessperformance.Theyalsomakeitpossibletoimprovethecustomerexperiencewithvoiceservices,whichisatoppriorityofmanyoperators.DuringtherecentlaunchofVoLTEinKorea,forexample,operatorsSKTandLGU+stressedsuperiorvoicequalityintheirmarketingcampaigns.Asvoiceservicesarethedominantsourceofrevenueformobileoperators,accountingforaround60%oftheirtotalrevenue,thereiseveryreasontoensureapositiveexperience.Goingforward,VoiceoverLTE(VoLTE)isthelogicalchoicetoprovidehigh-qualityvoiceservices over the same technology that is driving the data revolution.
1.2 VoLTE subscriptions will grow in parallel with LTE
OnceVoLTEcapablesmartphonesareintroducedonamassmarketscale,whichiswidelyexpectedin2013,thenumberofVoLTEsubscriptionsandtheintroductionofVoLTEservicesonLTEnetworks
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areprojectedtogrowquickly.ARCchartpredictedinMay2012thattherewillbeasmanyas74millionVoLTE-enabledsubscribersbytheendof2016,representingapproximately10%ofallLTEsubscriptions.
Takingintoaccountrevenue,qualityandOPEXdrivers,VoLTEistherighttechnologychoiceforoperatorstomaintaintheirexistingrevenuesandmoresignificantlytoenablenewbusinessopportunities(seesection2).TheunderlyingquestionisnotwhethertoimplementVoLTE,buthowandwhen,whichisdiscussedinsection3.
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Figure1:Althoughvoicerevenueisprojectedtodeclineslightly,itwillcontinuetobesignificant.(InfoneticsJune13.2012)
Figure2:LTEphoneuptakewillgrowsteadilyastheLTErolloutcontinues.(YankeeGroup2012)
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2. VoLTE offers key advantages in four main areas
VoLTE will typically be adopted in parallel with CS voice with a gradual transitiontoIMSVoLTE.ThetimingofthetransitionwillbecrucialforoperatorstoavoidlosingouttoOTTplayersandtakefulladvantage oftheadvantagesofVoLTE,whichcoverfourmainareas:
• Spectralefficiency:Spectrumrefarmingmakesitpossibletosignificantlyreducedeploymentcostsandhandletwiceasmanycalls with the same spectrum.
• Reuseofexisting2Gand3Gspectrumreducestheneedfornewspectrum
• Significantreductionindeploymentcostscomparedwithspectrum purchase
• Networkandplanningoptimizationcutscostsandenables future-proofnetworkmodernization
• Bettervoicecallquality:Shorterdelaysandfastercallset-uptimes improve the customer experience
• Richervoice:Creatingamultimediaenvironmentthatincludesvoice enables competition with OTT players
2.1 Higher spectral efficiencyImprovedspectralefficiencymakesitpossibleforVoLTEtohandletwiceasmanycalls,helpingtooptimizetheuseofradioresourcesandreducecosts.LTEofferstwicethespectralefficiencyof3G/HSPAandmorethan6timestheefficiencyofthelatestGSMtechnology.Thisfreesupmorecapacityfordata,whichinsomenetworksalreadyoutpacesvoicevolumebyafactorof50-100.AsbothdatavolumesandLTEdevicepenetrationgrow,spectralefficiencytocarrymorevoicewithlessbandwidthwillbecomeakeyadvantage.
ItispossibletousenewfrequenciesforVoLTE.Regulatorshavereallocatedinmanymarketsnewlowerfrequencybands(700,800MHz,oftencalled“digitaldividend”)whichcannowbeusedforLTE.BecauseoftheirgoodcoveragecharacteristicsthesefrequenciesareextremelysuitableforLTEvoiceimplementations.
Re-farmingfurtherimprovesspectralefficiency.WhenoperatorsintroducenewtechnologylikeLTEonthesamefrequencyspectrumtheyareusingfor3G,forexample,theycanrefarmthespectrumtouseitmoreefficiently.
Spectralefficiency Simplification Voicequality Richervoice
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2.2 SimplificationConsolidationisthekeytoOPEXsavingswithVoLTE.ByintegratingthevoiceanddatadomainsonthesameLTEnetwork,operatorscansignificantlyreducetheiroperatingcosts.Theintegrationofnetworkresources,theoptimizationofnetworkandservicemanagement,andthesimplificationofservicedeliveryallhelptoreducecosts.
Byrelyingononeradiotechnologyandusingre-farming,operatorscan adopt smart spectrum allocation to reuse existing spectrum andreduceoperationalcostsfortheradionetwork.Inaddition,transitioningtofullall-IPtechnologyresultsinsignificantsavingsontransmission costs.
Accordingtoourcalculations,theconsolidationofthecorenetworkenablesfurthercostbenefits:60%loweroperations&maintenancecosts,75%lowersitesupportcostsand65%lowerenergycosts.
2.3 Better voice call qualityThelowlatencyofLTEprovidesclearbenefitsforVoLTE.Shorterdelaysandfastercallset-uptimesenablehighqualityvoiceanddataconnections,helpingtoimprovethecustomerexperience.HighDefinition(HD)voiceisthedefaultwithVoLTE,andaspastexperiencehasshown,improvedqualityencourageslongertalktimeandreduceschurn.MuchlowerdelayandhighcapacityalsoenableHDvideoqualityforvideocalls,andthecallset-uptimerequiredforswitchingbetween communication methods such as chat and voice is much shorter.
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Figure3:LTEofferstwicethespectralefficiencyof3G/HSPA
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Internet-basedVoIPservicestendtogenerateagreaterloadonmobilenetworks,whichhasanadverseeffectonquality.BecauseOTTvoiceappstypicallyusemorenetworkresources,operatorsneedtoinvestinmorecapacitytohandleOTTvoicetraffic.Inaddition,thequalityofOTTvoiceisoftenvariable,andoperatorsenjoyanadvantageherebecausesubscribersoftenconsidertheirmobilevoiceservices more reliable.
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Figure5:Internet-basedVoIPservicesgenerateahigherloadonmobilenetworks.
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2.4 Richer voiceVoLTEandRichCommunicationsService(RCS)arebasedonthe sameIPMultimediasubsystem(IMS),soVoLTEismuchmorethatanIP-basedvariantofexistingCSmobileservice.Byenablingsophisticatedvoice-basedservices,itoffersnewrevenuepotentialas well as a customer experience that cannot be matched by OTT providersorCS-basedvoiceservicesalone.IMS-basedVoLTEsupportsanRCSmultimediaserviceportfolio,includingprivacy,buddylists,presence,videoshare,videocall,multimediamessaging,chat,filetransfer,andmanymore.
Someoftheseservices,inparticulartheonesincludedinRCS-e,orenhanced,werelaunchedrecentlyinSpain.RCS/RCS-earebothbasedonIMS,whichenablesafastlaunchofrichVoLTEserviceswhensufficientLTEcoverageisavailable.
ByimplementingVoLTE,operatorscantakefulladvantageofthecapabilitiesofsmartphonesthathaveanRCSclient.Allservicecapabilitiesareavailablebydefault,whichmakesitmucheasierforsubscriberstofindandselectattractivenewservices,significantlyloweringthethresholdforadoptingthem.WithOTTvoiceservices,subscribersneedtodownloaddefinedOTTclientsoftwareandselecttheservice.Thiscanbeaninvolvedprocessthatmanywillforget orforgo.
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3. How to evolve to VoLTE: Approaches to consider
The evolution to VoLTE is a process that can be made in several stepsandimplementedinseveralways.Someoperatorswillmakethedecisiontooffer,eitherinitiallyoroverthelongerterm,acombinationofCSvoiceandLTEdataonLTEdevices.Eventually,however,therevenue-generatingopportunitiesfromenrichedvoiceservicesforLTEsmartphonesarelikelytobesocompellingthatmost,ifnotall,operatorswilladoptfullIMS-basedVoLTE.Providingvoiceanddatasimultaneouslyoverthesamenetworkwillallowoperators to ensure an optimal customer experience.
ThefactorsaffectingthischoiceaswellasthepaceofdeploymentofVoLTEwilldependontheexistingmobiletechnology,whether2G/3G/HSPAorCDMA;theLTEspectrumavailableinagivenlocation,whichwillhaveanimpactofLTErolloutandcoverage;localmarketconditions;andtheoperator’sbusinessobjectives,whethertosticktobasicvoiceandsmsservicesorofferadvancedservices.Takingallthesefactorsintoaccount,therearethreemainapproachestointroducingvoiceservicesforLTEsubscribers:
• ImplementIMSVoLTEandmultimedia. The target with this approachisanall-IParchitectureandadvancedservices.Withthisapproach,3Gcoverageand/orcapacityareinadequatetoprovidethelevelofservicerequired,andLTEcoverageisalreadygoodandgrowingfast.
• ImplementCSFBforvoiceandIMSformultimedia,e.g.RCS in the initial stage and evolve to VoLTE when LTE coverage is nationwide. Thisapproachrequiresgood3Gcoverageandcapacityandsupportsastrategyofofferingadvancedservices.LTEcanbeused to provide extra data capacity in congested areas.
• ImplementCSFBoverthelongterm and evolve to VoLTE only whenthemarketdemandsit.Inthiscase,thereisnorequirementtogobeyondvoice,SMSandbasicdata.LTEcoverageislimited,andLTEistargetedonlyfordata.NationwideCScoverageisbasedmainly on 2G.
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The most common way to introduce voice service in early phase oftheLTEisCSFB,whichcanbeusedalsoforroamingaslongasnecessary.InCDMAmarkets,suchasNorthAmericaandJapan,CDMAoperatorsarerollingoutLTEandforexampleofferingCDMAvoicewithSimultaneousVoiceandLTE(SVLTE).FirstcommercialIMSVoLTEnetworkshavebeenlaunchedinSouth-KoreaandUS.InothermarketscommerciallaunchofIMSVoLTEisexpectedin2013andonwards.
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Figure6:Factsaffectingchoiceandtimingofoperator’sVoLTEdeployment
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4. Options for providing voice services to LTE smartphone subscribers
Asdescribedabove,thereareseveraldifferentoptions,basedoneitherCS,CSFBorfullVoLTEtechnology,forprovidingvoiceservicesto LTE smartphone subscribers.
4.1 Use CS technologies to provide voiceCSvoicemakestheintroductionofvoiceservicesinanLTEenvironmentfastandeasyasitisbasedontheoperator’sexistingvoicecoreenvironment.ThefirstLTE-capablesmartphonesalreadysupportvoicewithCSanddatawithLTE,andthusenableabridgetowards LTE.
4.1.1 Implement Simultaneous Voice and LTEWhenLTEisanoverlaytoaCDMAnetwork,thecurrentapproachtodeliveringvoiceisSimultaneousVoiceandLTE(SVLTE).Inthiscase,voiceserviceisdeployedasaCDMACSvoiceservicerunninginparallelwithLTEdataservices.Thissolutionisenabledbydual-modehandsetsandnoadditionalnetworkfunctionalityisneeded.Dual-mode handsets can conduct simultaneous LTE data sessions and legacy voice calls.
4.1.2 Use Circuit Switched Fall Back (CSFB) as a bridging technology to VoLTE
Withthisapproach,CSFBestablishesasignallingchannelbetweenthecircuit-switchedvoicecore(MobileSoftSwitch)andtheMobilityManagementEntity(MME)intheLTEpacketcorenetwork(EvolvedPacketCore).Thisallowshandsetsattachedtothepacket-switchedLTEnetworktochangeovertoaCSnetworkforincomingandoutgoing voice calls. Ongoing data sessions in LTE will also switch overto3G/HSPAnetwork,andwhenthevoicecallsends,thehandsetreturnstoLTE.SMSmessagesaredelivereddirectlyoverthesignallinglink,sonofallbackmechanismisrequired.
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4.2 Implement IMS-based VoLTEVoLTEputsIMSattheheartofthevoicecorenetwork,managingtheconnectivitybetweensubscribersandtheimplementationofpolicy control. The Telephony Application Server (TAS) manages voice servicesandsupplementaryservicessuchascallforwarding,callwaitandcalltransfer.
IMS-basedVoLTEalsoenablesaRichCommunicationsServices(RCS)offering.Foroperatorsrunningbothfixedandmobilenetworks,aVoLTEsolutioncanbringfurthervaluebyenablingasinglevoicesolutionforboththefixedandmobiledomainsandmakingitpossibletocreateaunifiedvoicecoresolutionthatprovidesserviceforallaccess domains.
4.2.1 Deploy VoLTE without full LTE network coverageWhenLTEnetworksarenotubiquitous,devicesareoftenconnectedtotheCSnetworkratherthantheLTEnetwork.Callcontinuityandservicesynchronizationbetweenthenetworksarethereforeimportantissues to bear in mind.
ThecorenetworkmustenableVoLTE-capableLTEhandsetstocontinue voice calls when subscribers leave an LTE coverage area. The 3GPP-standardizedSingleRadioVoiceCallContinuity(SRVCC)functionhandsoveranycallstartedinLTEtothelegacynetworkinordertoensure a continuous voice connection.
IMSVoLTEandcircuit-switchednetworksareexpectedtoprovidethesamevoiceservices.Inaddition,servicemanipulation,e.g.callforwardingactivation,needstobeanaccessagnostic.WhenaserviceisactivatedwithanLTEhandset,ithastobeactivatedonallmobilenetworksatthesametime(2G/3G/LTE).
Dependingondemand,itmaybeunnecessarytoloadIMSandHSSasthemajorityofvoiceservicesmaycontinuetobeprovidedbytheCSnetwork.UntilLTEnetworkcoverageisubiquitous,there-useofcurrentnetworkregisterscouldprovideopportunitiesforcostsavings.
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5. VoLTE solution: Part of NSN Liquid Net
NSN’sVoLTEsolutionreusesexistinginvestmentsandprovidesaseamlessexperienceforsubscriberswhen2G/3GandLTEnetworksare used in parallel and handovers are a common occurrence. This solutionisbasedontheabilitytoprovidefullIMSonanexistingcircuit-switchedvoiceroamingecosystem,enablingre-usabilitythatminimizes investment and operational costs. The solution is provided withtheOpenCoreSystem,partofNSNLiquidNetarchitecture,whichis built on COTS ATCA hardware and allows dynamic resource handling betweencurrentandnewnetworkfunctionsandservices.
IntheOpenCoreSystem,corevirtualizationisusedtobringmoreflexibilitytothecorebyrunningallthekeycomponentsonasingle,commonplatform.LiquidNetmanagesanddeliversservicesandcontent,dynamicallyprovidingthecapacityneededtoensurethebestcustomer experience at the lowest cost.
OperatorscanthereforeruntheMSS,IMSandEPConthesamephysicalATCAplatform,whichcutsOPEXbyreducingfootprintandenergy consumption. Capacity can be dynamically allocated to LTE subscribersusingeitherCSFBvoicecallscontrolledbyMSSorVoLTEcontrolledbyIMS.FurtherOPEXsavingscomefrommoreefficientnetworkmanagementoffewernetworkelements.
Forhybridoperators,theVoLTEsolutioncanbringevenmorevaluebyprovidingasinglevoicesolutionforbothdomains.Inthiscase,itispossibletobuildaunifiedvoicecoresolutioncapableofprovidingserviceforallaccessdomains.TheNSNVoLTEsolutionisfullycompliantwithGSMAIR.92andIR.94specifications,alsocommonlyknownastheGSMA’sVoLTEinitiative.
NSNGSMAspecification-compliantVoLTEsolutionwillmakeinterworkingstraightforwardandalsoensurethewidestchoiceofdevicesforendusers.Thissolutionenablesthefollowing:
• MobileCoretransitiontofullIMSarchitectureviaOpenCoreSystem,ensuringoptimizedexpenditureinCAPEXandOPEX.
• FullreuseofexistingbackendinfrastructureinvestmentswithaCSFBandVoLTEdeploymentstrategy.
• Voicefeatureparityacross2G/3GandLTEaccesstomaintainhighofend-usersatisfaction.
• FlexiblesolutionthatisMSCvendor-agnosticandcanbedeployedinanymarket.
• OpenCorearchitecturethatpromotesagradualmigrationofsubscriberstothenewIMS-baseddomain.
• Mostefficientwayfor3GPPproviderstoshiftexisting2G/3GvoiceservicestoanIMSarchitecture,which,inturn,enablesoperatorstotapintotheemergingvalue-addedRCSecosystem.
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6. ConclusionLTEisraisingthegameformobilebroadband.Itisthefirsteverglobalmobilebroadbandtechnology,andmeasuredinnetworks,devicesandsubscribers,LTEisachievingthefastesteveruptakeofanymobiletechnology.Itisalsothefirstradioaccesstechnologythatis100%packetbased,whichcombinedwiththeall-IPnetworkcore,translatesintogreaterefficiency.
VoLTE,whichdoesmuchmorethanmerelyreplicateCSvoice,willhaveasimilarimpact,enablingarichmultimediaportfoliothatincludesbrowser-basedappsforvoicecalls,chat,communicationsforlocation-basedservices,videoconferencing,etc.Inanutshell,VoLTEwillhelpoperatorsmaintainexistingrevenuesandmoresignificantly,createnew business opportunities and revenue streams.
Inmostmarkets,operatorswilladoptVoLTEinparallelwithCS.Theirgo-to-markettimingwillbecrucial.TheyneedtohavetheirVoLTEofferinginplaceattherighttimeastheLTEsmartphonesarealreadyinmarketandfortherightsegmentstocompetesuccessfullywithOTTplayers,gainnewrevenuewithrichmultimediaandvoiceservicesandachievethefullOPEXbenefitsofVoLTE.
ATCA–HWplatformisbasedonaseriesofAdvancedTCA™
CAPEX – Capital expenditure
CDMA–CodeDivisionMultipleAccess
COTS–commercialoff-the-shelfproduct
CS – Circuit Switched
CSFB–CircuitSwitchedFallback
EPC–EvolvedPacketCore
GSMA–GlobalSystemforMobileCommunications Association
HSPA–HighSpeedPacketAccess
HSS – Home Subscriber Server
IMS–IPMultimediaSubsystem
LTE – Long Term Evolution
MME–MobilityManagementEntity
MSS–MSCServer
NVS – NSN mobile VoIP Server (TAS)
OPEX – Operating expenditure
OTT – Over the Top
PS–PacketSwitched
PGW–PacketDataNetworkGateway
RCS(-e)–RichCommunicationSuite(-enhanced)
SGs–InterfacebetweenMMEandMSCserver
SGW – Serving Gateway
SRVCC–SingleRadioVoiceCallContinuity
SVLTE – Simultaneous voice over LTE
TAS – Telephony Application Server
Glossary of abbreviations
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©2013NokiaSolutionsandNetworks.Allrightsreserved.
Public NSNisatrademarkofNokiaSolutionsandNetworks.NokiaisaregisteredtrademarkofNokiaCorporation.Otherproductnamesmentionedinthisdocumentmaybetrademarksoftheirrespectiveowners,andtheyarementionedforidentificationpurposesonly.
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